1. Field of the Invention
The present invention relates to a data controller which manages the flow of text and electronic program guide data from the data supplier to the viewer's television tuner. In particular, the data controller of the invention accepts electronic program guide and text data from one or more local or remote sources, processes the data in its internal database manager, and formats the data for transmission to the viewer's television tuner preferably via the vertical blanking intervals of existing cable television channels.
2. Description of the Prior Art
Television text data services are readily available. Such services provide sports, weather, stock market, news, advertising and other information to the viewer's television for display to the viewer. Typically, the text data is provided to the cable head end by the text data service providers and then provided to the viewer via dedicated cable channels provided at the cable head end. At the cable head end, the text data from the different text data service providers is assigned to respective cable television channels available to the viewers, converted into a video signal, and then transmitted to the viewer's television via the assigned cable television channel in place of other programming. The viewer then tunes to the assigned cable television channel to receive the transmitted text data. Unfortunately, this technique wastes valuable video bandwidth for the transmission of the text data and is thus generally undesirable. Also, since the cable head end operator must create a video signal from the text data provided by the service providers prior to transmission of the text data to the viewer, the existing technique for providing text data to a viewer is quite tedious and expensive. A more efficient text data service is desired.
Other techniques for providing text data to viewers are known in the art. For example, closed captioned encoding techniques are used to transmit text data in synchronization with its associated video data by inserting the closed captioned text data into the vertical blanking interval of the video signal. In this manner, not only can synchronization be preserved, but also, additional bandwidth is not necessary for the transmission of the text data. However, the closed captioned text data must be inserted into the vertical blanking interval of the video signal by the producer of the video programming. As a result, the vertical blanking interval of the video signal cannot be used by the head end operator to insert other text data such as sports, weather, stock market, news, advertising and the like. An improved text data transmission technique is desired whereby such general text data may be inserted into the video signal at the cable head end for transmission to the viewer.
It is also known in the art to provide an electronic program guide (EPG) which provides the viewer with an on-screen listing of the upcoming television programs on the cable television channels available to the viewer. Typically, the EPG is provided by an EPG data service and the EPG data is converted into a video signal at the cable head end and transmitted to the viewer's television via a dedicated cable television channel. After tuning to the dedicated cable television channel, the viewer then must passively wait until the programming for the desired time period is displayed. In other words, this technique provides no mechanism for allowing the viewer to scroll through the EPG to the desired listing. Moreover, this technique also requires the cable head end operator to dedicate a separate cable television channel to the EPG data and to create video signals from the EPG data provided by the EPG service providers.
These problems with the transmission of EPG data have been addressed in the prior art by modulating the EPG data onto an FM carrier and transmitting that FM carrier with a video signal on one of the cable television channels. A dedicated peripheral device provided at the viewer's television tuner demodulates the EPG data from the FM carrier and stores the EPG data until the viewer requests presentation of the EPG data on the viewer's television. Upon selection of the EPG data, the EPG is displayed on the viewer's television in place of the other video programming. Since the EPG data is stored locally at the viewer's television, the viewer may scroll through the listings in the EPG until the desired listing is reached. While this technique does not require a separate dedicated cable television channel for the transmission of the EPG and allows the user to scroll through the EPG, an improved EPG transmission technique is desired which can be integrated with the viewer's normal cable television tuner so that a separate peripheral device dedicated to reception of the EPG is not necessary. Also, it is desired that the EPG data transmission be combined with the text data transmission to maximize efficiency.
In addition, it is also known to amplitude modulate the audio carrier or to frequency modulate an out-of-band carrier with control and authorization information from the head end controller for transmission to the viewers' cable television tuners. However, it is desired that the transmission of the control and authorization information also be integrated with the text data and EPG data transmission so that a single common data transmission/reception scheme may be used.
The present invention has been designed to meet these needs in the art.